The Patent Literature 1 discloses an adsorber. This adsorber includes heat medium tubes, in which heat medium flows, a sintered body, which is porous and is joined to outer surfaces of the heat medium tubes, and an adsorbent, which is held by the sintered body. Smooth tubes, each of which does not have a groove in an inner surface and an outer surface of the tube, are used as the heat medium tubes. The sintered body is formed by sintering metal powder particles such that the metal powder particles are joined together while air gaps are formed among the metal powder particles, and the metal powder particles and the heat medium tubes are joined together. In this prior art adsorber, the adsorbent is held by the sintered body to improve the heat conductivity between the adsorbent and the heat medium tube.
The heat conductivity between the adsorbent and the heat medium, which flows in the heat medium tube, significantly contributes to an adsorption capacity of the adsorber at the time of adsorbing a gas phase refrigerant into the adsorbent or the time of desorbing the gas phase refrigerant from the adsorbent. Thus, it has been demanded to improve the heat conductivity between the adsorbent and the heat medium.
However, in the prior art adsorber discussed above, since the outer surface of the heat medium tube is smooth, the amount of contraction of the metal powder particles at the time of sintering the metal powder particles becomes large. In such a case, the metal powder particles largely move along a boundary between the metal powder particles and the heat medium tube. Thus, a process of joining between the metal powder particles and the outer surface of the heat medium tube is interfered, and thereby a contact surface area between the metal powder particles and the heat medium tube becomes small. As a result, a heat resistance between the metal powder particles and the heat medium tube disadvantageously becomes large. Furthermore, since the inner surface of the heat medium tube is smooth, a heat transfer coefficient between the heat medium and the heat medium tube becomes disadvantageously small.